Multistate static random access memories (SRAMs) are memories in which data can be written and/or rewritten as often as desired. Generally, the memories are static because the memory state does not change with time as long as the power supply is on.
Also, each cell of the memory has a plurality of states which can be written into the cell and subsequently sensed. The major problem that arises with prior art multistate memories is the time required to read the information stored in the memory in order to keep the static power consumption reasonably low. Also, in most prior art multistate memories, the size is a problem because of the devices or circuitry required to provide the multiple states.
Accordingly, it would be highly advantageous to provide small, high speed multistate SRAMs and SRAM cells.
It is a purpose of the present invention to provide new and improved multistate SRAM cells.
It is another purpose of the present invention to provide new and improved multistate SRAM cells which are relatively small and compact.
It is still another purpose of the present invention to provide new and improved multistate SRAM cells which operate at relatively high speed.
It is a further purpose of the present invention to provide new and improved multistate SRAM cells which are connected into an SRAM that has a relatively high speed and high density.